Image carrying member unit and image forming apparatus therewith

Abstract

An image carrying member unit includes an image carrying member, a flange member, a shaft member, and a grounding member. The grounding member has a first bottom plate portion electrically connecting to the shaft member, and a pair of flat spring portions. Each flat spring portion has a first spring segment and a second spring segment bent from the tip end of the first spring segment via a second bent portion outward in the radial direction of the image carrying member to extend to approach the first bottom plate portion. Before insertion in the image carrying member, the distance between the second bent portions of the flat springs is smaller than the inner diameter of the image carrying member and the distance between tip end parts of the second spring segments is larger than the inner diameter of the image carrying member.

What is claimed is: 
     
       1. An image carrying member unit comprising:
 an image carrying member in a cylindrical shape, the image carrying member having a photosensitive layer formed on an outer circumferential surface thereof, the image carrying member having an opening at each end thereof; 
 a flange member having:
 a fitting portion fitted in the opening in the image carrying member; and 
 a through-hole along a rotation center of the image carrying member, 
 the flange member being electrically non-conductive and being fixed to each end of the image carrying member; 
 
 a shaft member inserted in the through-hole in the flange member; and 
 a grounding member fixed to the flange member, the grounding member electrically connecting together the image carrying member and the shaft member, 
 wherein 
 the grounding member has:
 a first bottom plate portion fixed to a tip end part of the fitting portion in a fitting direction thereof; 
 a pair of flat spring portions rising from the first bottom plate portion via a first bent portion in the fitting direction, the flat spring portions facing each other in a radial direction of the image carrying member, the radial direction being orthogonal to the fitting direction, 
 
 the first bottom plate portion has:
 a first projection portion extending toward the through-hole so as to approach and electrically connect to the shaft member, 
 
 the flat spring portions each has:
 a first spring segment extending from the first bent portion in the fitting direction; and 
 a second spring segment bent from a tip end of the first spring segment via a second bent portion outward in the radial direction of the image carrying member to extend in a direction opposite to the fitting direction so as to approach the first bottom plate portion, 
 
 before insertion in the image carrying member, a distance between the second bent portions of the flat spring portions is smaller than an inner diameter of the image carrying member and a distance between tip end parts of the second spring segments is larger than the inner diameter of the image carrying member. 
 
     
     
       2. The image carrying member unit according to  claim 1 , wherein
 the flat spring portions each have a slit extending from near a tip end part of the second spring segment through the second bent portion and the first spring segment to the first bottom plate portion. 
 
     
     
       3. An image forming apparatus comprising the image carrying member unit according to  claim 2 . 
     
     
       4. The image carrying member unit according to  claim 1 , wherein
 the flat spring portions each have a first contact segment extending from a tip end part of the second spring segment to make contact with an inner circumferential surface of the image carrying member. 
 
     
     
       5. An image forming apparatus comprising the image carrying member unit according to  claim 4 . 
     
     
       6. The image carrying member unit according to  claim 1 , wherein
 the grounding member is fixed to the flange member fixed to each end of the image carrying member, and a circuit board portion for controlling the image carrying member unit is arranged at one end side of the image carrying member, 
 at the one end side of the image carrying member, a predetermined distance is provided between the shaft member fixed to the flange member and the first projection portion of the grounding member, 
 at another end side of the image carrying member, the shaft member fixed to the flange member makes contact with the first projection portion of the grounding member, and 
 a distance between the circuit board portion and the shaft member at a position where these are closest to each other is larger than a distance between the shaft member and the first projection portion. 
 
     
     
       7. An image forming apparatus comprising the image carrying member unit according to  claim 6 . 
     
     
       8. The image carrying member unit according to  claim 1 , further comprising:
 a circuit board portion for controlling the image carrying member unit; 
 a grounding plate fixed to the flange member fixed to one end side of the image carrying member; and 
 the grounding member fixed to the flange member fixed to another end side of the image carrying member, 
 wherein 
 the grounding plate has:
 a second bottom plate portion fixed to an end part of the fitting portion in the fitting direction; 
 a second contact segment extending from the second bottom plate portion toward an inner circumferential surface of the image carrying member to make contact with the inner circumferential surface of the image carrying member at a position overlapping a non-image-formation region located outward of the photosensitive layer on the image carrying member in an axial direction thereof; and 
 a second projection portion extending from the second bottom plate portion toward the shaft member to face the shaft member across a predetermined distance, 
 
 at another end side of the image carrying member, the shaft member fixed to the flange member makes contact with the first projection portion, and 
 at one end side of the image carrying member, a distance between the circuit board portion and the shaft member at a position where these are closest to each other is larger than a distance between the shaft member and the second projection portion. 
 
     
     
       9. An image forming apparatus comprising the image carrying member unit according to  claim 8 . 
     
     
       10. An image forming apparatus comprising the image carrying member unit according to  claim 1 . 
     
     
       11. The image forming apparatus according to  claim 10 , further comprising:
 a developing roller arranged opposite the image carrying member and having a development region in which toner is supplied to the photosensitive layer; and 
 a gap forming member provided in each end part of the developing roller in an axial direction thereof and making contact with the non-image-formation region on the image carrying member, 
 wherein 
 the grounding plate makes contact with an inner circumferential surface of the image carrying member at a position not overlapping the gap forming member in the axial direction.